Russia will test launch a controversial missile over the next several weeks that U.S. officials say is raising new concerns about Moscow’s growing strategic nuclear arsenal and Russia’s potential violations of arms treaties.

The RS-26 missile is expected to be deployed with multiple supersonic, maneuvering warheads designed to defeat U.S. missile defenses in Europe, U.S. officials told Inside the Ring.

A House defense aide said the new missile appears to violate the 1987 Intermediate-range Nuclear Forces (INF) Treaty, based on recent tests and Russian statements that it is designed to thwart U.S. defenses. The treaty bans missiles with ranges of between 310 and 3,400 miles.

“The Russians are advertising this as a system capable of defeating U.S. missile defenses in Europe,” the aide said. “At the same time, the State Department is accepting Russia’s claim that this is an ICBM and doesn’t violate INF. It can’t be both.”

The Air Force National Space and Missile Intelligence Center reported recently that Russia’s June 6 test of an RS-26 was a test-firing of an intermediate-range missile disguised as an intercontinental ballistic missile.

Russian officials have denied that the RS-26 violates the INF Treaty, claiming it has a range greater than the treaty threshold of 3,410 miles.

However, Moscow officials in recent months have said the INF Treaty must be altered or scrapped to balance China’s growing arsenal of intermediate-range missiles. The Russians also have been quoted in state-controlled press reports as saying the new missile will be used to defeat and destroy U.S. and NATO missile defenses in Europe.

The Obama administration is deploying land- and sea-based defenses in and around Europe to counter Iranian long-range missiles.

Officials familiar with intelligence reports said the next test-firing of the RS-26 is expected in December.

In June, Russian Deputy Prime Minister Dmitry Rogozin described it as a “missile defense killer” after a successful test flight with dummy warheads.

The new missile will be equipped with three multiple independently targetable re-entry vehicles, or MIRVs. What is new is that the warheads are super-high-speed vehicles capable of maneuvering from missile interceptors. The maneuvering warheads are considered advanced technology that will increase the precision targeting of the missile system.

The missile also reportedly will be equipped with a high-performance fuel that boosts acceleration shortly after launch, a feature useful for avoiding anti-missile interceptors.

The U.S. officials commented on the missile development after Russia’s RIA Novosti news agency reported Oct. 3 that the next RS-26 test will be conducted before the end of the year from the Kapustin Yar test range.

The new missile is raising questions under the 2010 New Strategic Arms Reduction Treaty (START). The treaty does not prohibit modernizing strategic weapons but allows each side “to question” whether a new type of strategic arm is being developed.

Pentagon spokesman Lt. Col. Damienn Pickert declined to comment on the RS-26, citing a policy of not discussing intelligence matters.